It is a fact that today the world is moving rapidly towards renewable energy for electricity generation, mainly to reduce the severe effects of global warming.
Solar and the wind top the list. Not only commercial installations but also many people install solar PV panels on their homes to generate electricity for their homes as well as sell it to the grid to get the benefits.
It’s a common belief that with rising temperatures across the world, the impact of it on solar power generation would be positive but it is not true. The fact is solar panels power generation efficiency starts dropping as the mercury rises.
The PV solar panels available today are normally power tested at 250C. There is a term called as the temperature coefficient pMax, which reveals the performance of the solar panel w.r.t. to the ambient temperature variation. The value is given by the manufacturer which is normally in the negative percentage. Suppose if this value is -0.5%, then for every 1-degree rise, the panels power output is expected to reduce by 0.5%. There are different types of solar panels available in the market with different temperature coefficient from -0.20% to -0.50%.
Now let’s understand why is it so? Photovoltaic cells start functioning when the photons from the sun rays activate the electrons on the solar panels, i.e. electrons change their form from resting state to excited state, which results into power generation. This energy is captured by the cells. But when the temperature rises, the resting state of the electrons goes up. As a result, the time difference between the resting state and excited state is smaller, thus the panels produce less energy.
To avoid the heating of the solar panels sufficient cooling needs to be provided for the panels. Many commercial installations have an automated ventilation systems or fans to cool the panels on a hot sunny day or when the ambient temperature rises beyond a particular point. It is very important to install the panels where there is a good amount of natural ventilation. Actually, this problem is more for the homeowners with rooftop solar systems in the areas where it’s less windy and surrounded by tall buildings.